rtc_pl031.cc

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/*
 * Copyright (c) 2010-2012 ARM Limited
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 *
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 * not be construed as granting a license to any other intellectual
 * property including but not limited to intellectual property relating
 * to a hardware implementation of the functionality of the software
 * licensed hereunder.  You may use the software subject to the license
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 * met: redistributions of source code must retain the above copyright
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#include "dev/arm/rtc_pl031.hh"
 
#include "base/intmath.hh"
#include "base/time.hh"
#include "base/trace.hh"
#include "debug/Checkpoint.hh"
#include "debug/Timer.hh"
#include "dev/arm/amba_device.hh"
#include "mem/packet.hh"
#include "mem/packet_access.hh"
 
namespace gem5
{
 
PL031::PL031(const Params &p)
    : AmbaIntDevice(p, 0x1000), lastWrittenTick(0), loadVal(0), matchVal(0),
      rawInt(false), maskInt(false), pendingInt(false),
      matchEvent([this]{ counterMatch(); }, name())
{
    // Make a temporary copy so mkutctime can modify it.
    struct tm local_time = p.time;
    timeVal = mkutctime(&local_time);
}
 
 
Tick
PL031::read(PacketPtr pkt)
{
    assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
    assert(pkt->getSize() <= 4);
    Addr daddr = pkt->getAddr() - pioAddr;
    uint32_t data;
 
    DPRINTF(Timer, "Reading from RTC at offset: %#x\n", daddr);
 
    switch (daddr) {
      case DataReg:
        data = timeVal +
            ((curTick() - lastWrittenTick) / sim_clock::as_int::s);
        break;
      case MatchReg:
        data = matchVal;
        break;
      case LoadReg:
        data = loadVal;
        break;
      case ControlReg:
        data = 1; // Always enabled otherwise there is no point
        break;
      case IntMask:
        data = maskInt;
        break;
      case RawISR:
        data = rawInt;
        break;
      case MaskedISR:
        data = pendingInt;
        break;
      default:
        if (readId(pkt, ambaId, pioAddr)) {
            // Hack for variable sized access
            data = pkt->getUintX(ByteOrder::little);
            break;
        }
        panic("Tried to read PL031 at offset %#x that doesn't exist\n", daddr);
        break;
    }
 
    pkt->setUintX(data, ByteOrder::little);
    pkt->makeAtomicResponse();
    return pioDelay;
}
 
Tick
PL031::write(PacketPtr pkt)
{
    assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
    assert(pkt->getSize() <= 4);
    Addr daddr = pkt->getAddr() - pioAddr;
    DPRINTF(Timer, "Writing to RTC at offset: %#x\n", daddr);
 
    switch (daddr) {
      case DataReg:
        break;
      case MatchReg:
        matchVal = pkt->getLE<uint32_t>();
        resyncMatch();
        break;
      case LoadReg:
        lastWrittenTick = curTick();
        timeVal = pkt->getLE<uint32_t>();
        loadVal = timeVal;
        resyncMatch();
        break;
      case ControlReg:
        break; // Can't stop when started
      case IntMask:
        maskInt = pkt->getLE<uint32_t>();
        break;
      case IntClear:
        if (pkt->getLE<uint32_t>()) {
            rawInt = false;
            pendingInt = false;
        }
        break;
      default:
        if (readId(pkt, ambaId, pioAddr))
            break;
        panic("Tried to read PL031 at offset %#x that doesn't exist\n", daddr);
        break;
    }
 
    pkt->makeAtomicResponse();
    return pioDelay;
}
 
void
PL031::resyncMatch()
{
    DPRINTF(Timer, "Setting up new match event match=%d time=%d\n", matchVal,
            timeVal);
 
    uint32_t seconds_until = matchVal - timeVal;
    Tick ticks_until = sim_clock::as_int::s * seconds_until;
 
    if (matchEvent.scheduled()) {
        DPRINTF(Timer, "-- Event was already schedule, de-scheduling\n");
        deschedule(matchEvent);
    }
    schedule(matchEvent, curTick() + ticks_until);
    DPRINTF(Timer, "-- Scheduling new event for: %d\n", curTick() + ticks_until);
}
 
void
PL031::counterMatch()
{
    DPRINTF(Timer, "Counter reached zero\n");
 
    rawInt = true;
    bool old_pending = pendingInt;
    pendingInt = maskInt & rawInt;
    if (pendingInt && !old_pending) {
        DPRINTF(Timer, "-- Causing interrupt\n");
        interrupt->raise();
    }
}
 
void
PL031::serialize(CheckpointOut &cp) const
{
    DPRINTF(Checkpoint, "Serializing Arm PL031\n");
    SERIALIZE_SCALAR(timeVal);
    SERIALIZE_SCALAR(lastWrittenTick);
    SERIALIZE_SCALAR(loadVal);
    SERIALIZE_SCALAR(matchVal);
    SERIALIZE_SCALAR(rawInt);
    SERIALIZE_SCALAR(maskInt);
    SERIALIZE_SCALAR(pendingInt);
 
    bool is_in_event = matchEvent.scheduled();
    SERIALIZE_SCALAR(is_in_event);
 
    Tick event_time;
    if (is_in_event){
        event_time = matchEvent.when();
        SERIALIZE_SCALAR(event_time);
    }
}
 
void
PL031::unserialize(CheckpointIn &cp)
{
    DPRINTF(Checkpoint, "Unserializing Arm PL031\n");
 
    UNSERIALIZE_SCALAR(timeVal);
    UNSERIALIZE_SCALAR(lastWrittenTick);
    UNSERIALIZE_SCALAR(loadVal);
    UNSERIALIZE_SCALAR(matchVal);
    UNSERIALIZE_SCALAR(rawInt);
    UNSERIALIZE_SCALAR(maskInt);
    UNSERIALIZE_SCALAR(pendingInt);
 
    bool is_in_event;
    UNSERIALIZE_SCALAR(is_in_event);
 
    Tick event_time;
    if (is_in_event){
        UNSERIALIZE_SCALAR(event_time);
        schedule(matchEvent, event_time);
    }
}
 
} // namespace gem5